Roof coverings are frequently subjected to stresses that can cause tearing, for example, during the manufacturing process, from rough handling when they are applied on a roof, and from the effects of people walking on the roof after they have been applied. Therefore, it would be desirable to produce roof coverings having improved tear strength to withstand tearing under these and other stressful conditions.
U.S. Pat. No. 4,079,158 to Kennepohl et al., issued Mar. 14, 1978, discloses asphalt roofing shingles in which sulfur is added to the asphalt in an amount between 10% and 55% by weight. The addition of the sulfur to the asphalt is said to provide the shingles with greater fire resistance. There is no suggestion to use sulfur to improve the tear strength of the shingles.